To establish the proof of concept that Nutrabiotix fiber is safe and well tolerated, promotes gut health by increasing production of short chain fatty acids and changes colonic microbiota composition in favor of bifidobacteria, improves bowel habit and increase in stool weight. To this end, we will conduct a randomized, double blind, controlled, dose ranging, 3 arm trial in 120 healthy subjects comparing two doses of the Nutrabiotix fiber to psyllium fiber. PUBLIC HEALTH RELEVANCE: The completion of this project will prove the efficacy and tolerability of Nutrabiotix fiber in humans and will form the basis of commercializing a well tolerated natural carbohydrate product with targeted delivery to the colon that promotes "gut health" and potentially, prevents and treats colonic diseases where changes in the gut microbiota and/or colonic milieu play a key pathogenic role.